How to test tag attributes using assert_select

Wednesday, September 10th, 2008

There’s undoubtedly a smarter way to do this, but I couldn’t figure it out. I’m doing a functional (controller) test for one of my rails pages. I want to make sure that the picture coming back is exactly 224 pixels high.

I couldn’t find a way to do this using the assert_select syntax, but this workaround seems to work:


  def test_picture_height
    assert_select "div.secondary div.lead_picture img[height]" do |height|
      # pull the tag -- this gives you the whole img tag
      @h = height.to_s
      # extract the height
      @h.gsub!(/.*height="(.*?)".*$/, '\1')
      #run the test
      assert_equal @h, "224"
    end
  end

This can be tightened up, but I left it explicit so that I could understand what I was going. The assert select makes sure that I’m setting the height. The block makes sure that it’s equal to 224.

Are there easier ways to do this?

One Response to “How to test tag attributes using assert_select”

  1. Paul Says:

    Any reason this doesn’t work?

    assert_select ‘image[height=”224″]’

    See: http://labnotes.org/svn/public/ruby/rails_plugins/assert_select/cheat/assert_select.html

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